Collapsible plastic bags are often used to store liquid products such as chemicals, soft drink syrup, and food condiments. The plastic bags are typically housed in a container or box to aid in handling and dispensing of the product. Such bags are referred to in the art as "bag-in-box bags."
The plastic bags also have a spout for filling and dispensing the product within the bag. Generally, to dispense product from bag-in-box bags, vacuum pump systems are often utilized. To aid in dispensing product from the container, evacuation channels are often placed within the bag. Evacuation channels are typically elongate cylindrical tubes or flat strips with protruding ribs defining grooves. Typically, one end of the evacuation channel is disposed transverse to, or is connected to the spout, and the other end of the evacuation channel extends into the cavity of the bag. As the bag is emptied by the force of the vacuum pump, portions of the bag collapse unevenly, tending to leave pockets of product, typically liquid, which may become isolated from the rest of the liquid in the container. The evacuation channel, however, forms a conduit which cannot be closed off by the vacuum pressure on the walls of the bag. In this manner the entire chamber of the flexible bag remains in communication with the spout at all times during the dispensing such that all product within the bag can be removed.
Prior attempts to provide such bags are disclosed in U.S. Pat. Nos. 4,601,410; 5,647,511 and 5,749,493. U.S. Pat. Nos. 4,601,410 and 5,647,511 disclose a liquid container with an evacuation unit. In both the '410 and '511 patents, the evacuation unit is shown attached directly to the spout by a mounting ring. Several problems have been encountered with these types of evacuation units. For example, during the filling process, which is typically done in a high speed and high pressure process, the evacuation unit is susceptible of being dislodged from the spout thereby rendering the evacuation unit inoperative. Also, the attaching ring can impede the flow of liquid during the filling process thereby slowing the filling process.
U.S. Pat. No. 5,749,493 discloses an evacuation unit positioned within a bag and transverse and perpendicular to a spout in the bag. Because the evacuation unit is positioned in a location that is in line with the incoming fluid during the filling process, it is susceptible of being dislodged from its mounting to the container thereby rendering it ineffective.
Other designs and configurations, beyond the three enumerated above, have been utilized by the flexible container industry but those designs have a number of inherent flaws. Foremost among those problems is the requirement of manual insertion of the evacuation channel after the container has been filled with liquid contents. This is highly undesirable because it adds another step to the manufacturing process and increases the labor costs.
For the aforementioned reasons, it is desirable to produce a flexible container with an evacuation channel that does not readily become dislodged during the filling step and does not significantly interfere with the rate of filling the container.